/*
* Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.protocol.bgp.parser.impl.message;
import static java.util.Objects.requireNonNull;
import com.google.common.base.Preconditions;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import java.util.ArrayList;
import java.util.List;
import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
import org.opendaylight.protocol.bgp.parser.BGPError;
import org.opendaylight.protocol.bgp.parser.BGPParsingException;
import org.opendaylight.protocol.bgp.parser.BgpTableTypeImpl;
import org.opendaylight.protocol.bgp.parser.impl.message.update.AsPathAttributeParser;
import org.opendaylight.protocol.bgp.parser.impl.message.update.NextHopAttributeParser;
import org.opendaylight.protocol.bgp.parser.impl.message.update.OriginAttributeParser;
import org.opendaylight.protocol.bgp.parser.spi.AttributeRegistry;
import org.opendaylight.protocol.bgp.parser.spi.MessageParser;
import org.opendaylight.protocol.bgp.parser.spi.MessageSerializer;
import org.opendaylight.protocol.bgp.parser.spi.MessageUtil;
import org.opendaylight.protocol.bgp.parser.spi.MultiPathSupportUtil;
import org.opendaylight.protocol.bgp.parser.spi.PathIdUtil;
import org.opendaylight.protocol.bgp.parser.spi.PeerSpecificParserConstraint;
import org.opendaylight.protocol.util.ByteBufWriteUtil;
import org.opendaylight.protocol.util.Ipv4Util;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Prefix;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.PathId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Update;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.UpdateBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.Attributes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.Nlri;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.NlriBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.WithdrawnRoutes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.WithdrawnRoutesBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev180329.Ipv4AddressFamily;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev180329.UnicastSubsequentAddressFamily;
import org.opendaylight.yangtools.yang.binding.Notification;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* LENGTH fields, that denote the length of the fields with variable length, have fixed SIZE.
*
* @see BGP-4 Update Message Format
*/
public final class BGPUpdateMessageParser implements MessageParser, MessageSerializer {
private static final Logger LOG = LoggerFactory.getLogger(BGPUpdateMessageParser.class);
public static final int TYPE = 2;
private static final int WITHDRAWN_ROUTES_LENGTH_SIZE = 2;
private static final int TOTAL_PATH_ATTR_LENGTH_SIZE = 2;
private final AttributeRegistry reg;
public BGPUpdateMessageParser(final AttributeRegistry reg) {
this.reg = requireNonNull(reg);
}
@Override
public Update parseMessageBody(final ByteBuf buffer, final int messageLength) throws BGPDocumentedException {
return parseMessageBody(buffer, messageLength, null);
}
@Override
public void serializeMessage(final Notification message, final ByteBuf bytes) {
Preconditions.checkArgument(message instanceof Update, "Message needs to be of type Update");
final Update update = (Update) message;
final ByteBuf messageBody = Unpooled.buffer();
final List withdrawnRoutes = update.getWithdrawnRoutes();
if (withdrawnRoutes != null) {
final ByteBuf withdrawnRoutesBuf = Unpooled.buffer();
withdrawnRoutes.forEach(withdrawnRoute -> writePathIdPrefix(withdrawnRoutesBuf, withdrawnRoute.getPathId(),
withdrawnRoute.getPrefix()));
messageBody.writeShort(withdrawnRoutesBuf.writerIndex());
messageBody.writeBytes(withdrawnRoutesBuf);
} else {
messageBody.writeZero(WITHDRAWN_ROUTES_LENGTH_SIZE);
}
if (update.getAttributes() != null) {
final ByteBuf pathAttributesBuf = Unpooled.buffer();
this.reg.serializeAttribute(update.getAttributes(), pathAttributesBuf);
messageBody.writeShort(pathAttributesBuf.writerIndex());
messageBody.writeBytes(pathAttributesBuf);
} else {
messageBody.writeZero(TOTAL_PATH_ATTR_LENGTH_SIZE);
}
final List nlris = update.getNlri();
if (nlris != null) {
nlris.forEach(nlri -> writePathIdPrefix(messageBody, nlri.getPathId(), nlri.getPrefix()));
}
MessageUtil.formatMessage(TYPE, messageBody, bytes);
}
private void writePathIdPrefix(final ByteBuf byteBuf, final PathId pathId, final Ipv4Prefix ipv4Prefix) {
PathIdUtil.writePathId(pathId, byteBuf);
ByteBufWriteUtil.writeMinimalPrefix(ipv4Prefix, byteBuf);
}
/**
* Parse Update message from buffer.
* Calls {@link #checkMandatoryAttributesPresence(Update)} to check for presence of mandatory attributes.
*
* @param buffer Encoded BGP message in ByteBuf
* @param messageLength Length of the BGP message
* @param constraint Peer specific constraints
* @return Parsed Update message body
*/
@Override
public Update parseMessageBody(final ByteBuf buffer, final int messageLength,
final PeerSpecificParserConstraint constraint) throws BGPDocumentedException {
Preconditions.checkArgument(buffer != null && buffer.isReadable(),
"Buffer cannot be null or empty.");
final UpdateBuilder builder = new UpdateBuilder();
final boolean isMultiPathSupported = MultiPathSupportUtil.isTableTypeSupported(constraint,
new BgpTableTypeImpl(Ipv4AddressFamily.class, UnicastSubsequentAddressFamily.class));
final int withdrawnRoutesLength = buffer.readUnsignedShort();
if (withdrawnRoutesLength > 0) {
final List withdrawnRoutes = new ArrayList<>();
final ByteBuf withdrawnRoutesBuffer = buffer.readBytes(withdrawnRoutesLength);
while (withdrawnRoutesBuffer.isReadable()) {
final WithdrawnRoutesBuilder withdrawnRoutesBuilder = new WithdrawnRoutesBuilder();
if (isMultiPathSupported) {
withdrawnRoutesBuilder.setPathId(PathIdUtil.readPathId(withdrawnRoutesBuffer));
}
withdrawnRoutesBuilder.setPrefix(Ipv4Util.prefixForByteBuf(withdrawnRoutesBuffer));
withdrawnRoutes.add(withdrawnRoutesBuilder.build());
}
builder.setWithdrawnRoutes(withdrawnRoutes);
}
final int totalPathAttrLength = buffer.readUnsignedShort();
if (withdrawnRoutesLength == 0 && totalPathAttrLength == 0) {
return builder.build();
}
if (totalPathAttrLength > 0) {
try {
final Attributes attributes
= this.reg.parseAttributes(buffer.readSlice(totalPathAttrLength), constraint);
builder.setAttributes(attributes);
} catch (final RuntimeException | BGPParsingException e) {
// Catch everything else and turn it into a BGPDocumentedException
throw new BGPDocumentedException("Could not parse BGP attributes.", BGPError.MALFORMED_ATTR_LIST, e);
}
}
final List nlri = new ArrayList<>();
while (buffer.isReadable()) {
final NlriBuilder nlriBuilder = new NlriBuilder();
if (isMultiPathSupported) {
nlriBuilder.setPathId(PathIdUtil.readPathId(buffer));
}
nlriBuilder.setPrefix(Ipv4Util.prefixForByteBuf(buffer));
nlri.add(nlriBuilder.build());
}
if (!nlri.isEmpty()) {
builder.setNlri(nlri);
}
final Update msg = builder.build();
checkMandatoryAttributesPresence(msg);
LOG.debug("BGP Update message was parsed {}.", msg);
return msg;
}
/**
* Check for presence of well known mandatory path attributes
* ORIGIN, AS_PATH and NEXT_HOP in Update message
*
* @param message Update message
* @throws BGPDocumentedException
*/
private static void checkMandatoryAttributesPresence(final Update message) throws BGPDocumentedException {
requireNonNull(message, "Update message cannot be null");
final Attributes attrs = message.getAttributes();
if (message.getNlri() != null) {
if (attrs == null || attrs.getCNextHop() == null) {
throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "NEXT_HOP",
BGPError.WELL_KNOWN_ATTR_MISSING,
new byte[] { NextHopAttributeParser.TYPE });
}
}
if (MessageUtil.isAnyNlriPresent(message)) {
if (attrs == null || attrs.getOrigin() == null) {
throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "ORIGIN",
BGPError.WELL_KNOWN_ATTR_MISSING,
new byte[] { OriginAttributeParser.TYPE });
}
if (attrs.getAsPath() == null) {
throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "AS_PATH",
BGPError.WELL_KNOWN_ATTR_MISSING,
new byte[] { AsPathAttributeParser.TYPE });
}
}
}
}